The phrase "small stack" refers to a small amount of something, like a tiny pile or collection. It can also describe someone or something that has less power, influence, or resources compared to others. Full definition
I will usually spread them out on the dining room table in small stacks of 3 - 4 and place a strip of wax paper loosely over the top. (shelovesbiscotti.com)
This pair are made from luxurious suede with an almond toe and small stacked heel. (reiss.com)
The dog area uses smaller stacked cages, and most dogs taken in by the group are large bully breeds. (iheartcats.com)